1. Field of the Invention
The present invention relates to a gasket which is installed, for example, to a male thread section of a tube joint and which makes it possible to effectively seal opposing surfaces at a connecting portion between the tube joint and another member when the tube joint is connected to the other member by the aid of the male thread section.
2. Description of the Related Art
A gasket has been hitherto used as a member that is installed, for example, to a male thread section of a tube joint and which seals a connecting portion by being interposed between the tube joint and another member when the tube joint is connected to the other member by the aid of the male thread section.
A conventional gasket structure is disclosed, for example, in Japanese Laid-Open Utility Model Publication No. 5-73362, and comprises a ring-shaped core section formed by a hard material such as a metal, and a covering section that covers an upper surface, a lower surface, and a circular inner circumferential surface of the core section with an elastically deformable material such as nitrile rubber.
Another gasket structure is disclosed in Japanese Laid-Open Patent Publication No. 2000-145969, and has a flat metal thin plate having a circular bore hole formed at a central portion and further having a protruding bead composed of an adhesive formed on a joining surface disposed adjacent to the bore hole of the metal thin plate.
Japanese Laid-Open Patent Publication No. 10-501873 (PCT) (WO95/34775) also discloses a gasket, comprising a bead having a lateral cross-sectional shape formed with a flat bottom surface, two inclined side surfaces extending upwardly and inclining inwardly from a portion thereof that intersects with the bottom surface, and a convexly curved top surface adjoining the side surfaces.
However, when the gaskets according to the conventional techniques disclosed in Japanese Laid-Open Utility Model Publication No. 5-73362, Japanese Laid-Open Patent Publication No. 2000-145969, and Japanese Laid-Open Patent Publication No. 10-501873 (PCT) (WO95/34775) are assembled, for example, to a male thread section of another member that extends vertically downward, the gasket tends to fall or drop off during transport after the gasket has been installed onto the male thread section. This occurs because the bore hole, which is formed at a central portion of the metal thin plate (core section) of the gasket has an inner diameter that is larger than an outer diameter of the male thread section to which the gasket is installed.